1. Field of the Invention
The present invention relates to dobbies and other weaving mechanisms of the negative type and more particularly to the drawing device interposed between each of the members for maneuvring the mechanisms and a corresponding heddle frame mounted on the associated weaving machine.
2. History of the Related Art
It is known that a weaving mechanism of the negative type ensures positive control of the frames only in one direction of their reciprocating stroke, with the result that it is necessary to provide elastic elements which are placed in tension during positive actuation so as to effect the return of each frame as soon as the corresponding maneuvring member of the mechanism ceases its action.
In practice, these elastic elements are spring systems including a plurality of springs maintained between two hooking elements. One of the hooking elements is suitably fastened to the fixed structure of the weaving machine, while the other is secured either with the end of a control cable coupled to each heddle frame, or with a rocking guide lever disposed along path of the cable between the frame and the spring system.
It should be observed that, to allow the weaving machines to operate at very high speeds, there is a tendency, at present, to employ increasingly powerful spring systems, which results in both the springs of the systems and the control cables breaking more frequently. Now, it is difficult to repair these operational failures, as this involves dismantling and subsequent remounting a large number of springs on which a very high tension is exerted.